1. Technical Field
Example embodiments of the present invention relate to a stereo matching method and apparatus for generating binocular disparity between pixels of left and right images, and more particularly to a method and apparatus for feature-based stereo matching capable of forming a depth map at a high speed without requiring calibration.
2. Related Art
In general, stereo matching refers to a process of obtaining an accurate, reliable disparity map by estimating disparity between correspondence points of two images obtained from different points of view using the same method as that of recognizing a distance of an object with two human eyes.
Further, it is possible to restore a three-dimensional (3D) image having a sense of depth by generating a depth map using the disparity map. Such stereo matching methods may be largely divided into area-based methods and feature-based methods. A feature-based method may be comparatively free from many of the limitations of an area-based method, thereby generating a more accurate, robust depth map. However, only a relatively sparse depth map can be generated in the feature-based method. Accordingly, in general, although the area-based method differs according to an application, it may be used to generate a dense depth map over the entire image. Therefore, the area-based method is preferred.
However, the area-based method requires a calibration process of constantly making an epipolar line consistent. Because depth values of all areas of an image are calculated, the area-based method requires a longer calculation time than the feature-based method. Under the assumption that the following conditions are satisfied, there is a disadvantage in that the stereo matching is performed.                A light source should be a point light source at an infinite distance.        An object within a scene should have a Lambertian surface.        Distortion in binocular color tones and characteristics should be comparatively small.        
There are techniques for recognizing a user's gesture using active sensing technology using a time of flight (TOF) camera, an infrared ray (IR) laser, or the like as well as stereo matching. However, there is a disadvantage in that the TOF camera is very expensive and the laser may impose a burden on the user's eyes. Further, there is a problem in that high-precision processing technology is required because it is difficult to manufacture the TOF camera and the laser in a thin, compact size.